These slides were presented for the webinar CO2 EOR and the transition to carbon storage which was presented by Dr Ernie Perkins, a geologist based in Alberta, Canada, with over 20 years experience in carbon dioxide sequestration and acid gas/EOR. Ernie currently works for both the Global CCS Institute and Alberta Innovates Technology Futures and presented an informative and educational dive into the realities and science of EOR. The webinar can be viewed by visiting the Global CCS Institute website (http://www.globalccsinstitute.com/community/events/2011/08/17/co2-eor-and-transition-carbon-storage).

1. GLOBAL CCS INSTITUTE
THE CO2 EOR – CCS PLAN HOPE
• CO2 EOR can produced significant amounts of
incremental oil.
• After production is halted, significant amount of CO2
remains and can be considered stored.
• Potentially, the field can become a CCS site.
50
45
40
35
Curre nt production at 35-year high
30
25
Ve rtical Infills
20
Actual
15
Pre -CO2
Prim ary & Waterflood Horiz Infills Wa t e rf lo o d
10 Im pro v e m e nt
5
0
Jan-55 Jan-61 Jan-67 Jan-73 Jan-79 Jan-85 Jan-91 Jan-97 Jan-03 Jan-09 Jan-15
Source: EnCana Corporation Data after Jan-08 are projections.

2. GLOBAL CCS INSTITUTE
CONTENTS
1. CO2 and Oil Properties
2. Reservoir Screening and Development
3. Joffre – an example
4. Transition to CO2 storage - Issues
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3. GLOBAL CCS INSTITUTE
KEY CO2 – OIL PROPERTIES FOR EOR
• CO2 Density (liquid or dense phase) is
close to, but lighter than oil and water.
Efficient sweep of new portion of
reservoir.
X Must be in liquid or dense phase region.
• CO2 is miscible with oil at high
pressures and immiscible at lower P.
X MMP is higher with heavier oil.
X Reservoir heterogeneity means that P
must be significantly above MMP
Miscibility and lower CO2 density results
in oil swelling.
? Lower MMP through new technologies.
? New technologies to recover at partially
miscible conditions.
? Asphaltenes, waxes, mineral scales,
etc, can precipitate due to CO2
presence. Lab work is needed to
evaluate.
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4. GLOBAL CCS INSTITUTE
KEY OIL - CO2 – WATER PROPERTIES
• CO2 Viscosity (liquid or dense phase)
is typically in the range of 0.5 to 0.09
cp (higher than gas, but much lower
than water and oil).
X Can result in fingering, thus need water
injection for control.
• Mobility ratio (Oil / Water viscosity
ratio) controls recovery – can be
improved through increasing water
viscosity (polymer addition, etc). New
Technologies.
LL Lower (heavier) Liquid
• Oil is a complex mixture of UL Higher (lighter) Liquid
hydrocarbons. The composition varies V CO2 rich vapour
significantly even in the same reservoir.
This results in complex phase
behaviour when CO2 is present.
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5. GLOBAL CCS INSTITUTE
RESERVOIR PROPERTIES
• Pressure and temperature control miscibility.
• Relative permeability effects can impact effect of CO2
injection. Hysteresis effects are critical.
• The formation will exhibit either water-wet, oil-wet or
mixed wettability, which controls recovery and fluid
injectivity.
• Laboratory evaluations are very important.
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6. GLOBAL CCS INSTITUTE
IMPLICATIONS OF OIL - CO2 PROPERTIES
Displacement Direction
Miscibility
Injected CO2 with Oil Oil with
Zone Oil
CO2 Components condensed CO2
``Single Phase``
Miscibility Zone size changes with time.
Several CO2 – oil phases can exist simultaneously.
This leads to a rather
simplified snapshot of the
reservoir recovery
process at a given time.
Once breakthrough has
occurred, some form of
WAG (water alternating
gas) will be implemented.
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7. GLOBAL CCS INSTITUTE
A SLIGHTLY MORE REALISTIC SNAPSHOT
OF THE RESERVOIR 4.2.2
Figure
Vertical Water
Vertical Injector
Hz Producer
Producer Hz CO2 Injector
Midale
Anhydrite
Midale CO2 & Oil CO2
Marly Oil
& CO2
Oil & CO2
Water
Midale Vert Crosswell
Vuggy
Water
Frobisher
• Increasing reservoir heterogeneities result in more complex well geometries
and production methods.

8. GLOBAL CCS INSTITUTE
TECHNICAL & ECONOMIC SCREENING
• Average reservoir pressure and MMP.
• Well patterns and stage of depletion.
• Residual oil saturation.
• Reservoir wettability.
• Reservoir heterogeneities and inter-well
continuity.
• Ability to inject and produce fluids at economical
rates.
• Cost and amount of CO2.
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9. GLOBAL CCS INSTITUTE
RESERVOIR DEVELOPMENT FOR CO2 EOR
• Gravity dominated floods vs. pattern floods.
• Wellhead & bottom hole injection pressure.
• Effects of impure gas streams.
• Pattern modifications
− Infill drilling
− Horizontal wells
− Pattern balancing
• Production wells – conversion to flowing.
• Phased-in or delayed field development.
• WAG optimization and CO2 slug size
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10. GLOBAL CCS INSTITUTE
RELATIVE NEED FOR FACILITIES
Primary Waterflood CO2 EOR
Production Wells (infill)
Injection Wells (infill)
Water-Oil Separation
Gas separation
Water Injection
Water Recycle
Makeup Water
CO2 Source
Gas Compression
Indicates that these facilities are needed.
Number indicates relative amount.
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11. GLOBAL CCS INSTITUTE
JOFFRE CO2 EOR
• Currently a light oil CO2 miscible flood.
• As of 2009,
– 57.6 bcf CO2 injected, 40.4 bcf CO2
produced, resulting in a 30% storage
factor.
– Current Oil production ~450 bbls/day
– 4.86 MMbbls recovered.
– 11.5% OOIP recovered.
– Goal is 16.5% OOIP recovery
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12. GLOBAL CCS INSTITUTE
TRANSITION TO CCS
• Long term planning is critical. CO2 EOR tries to
maximize oil production and minimize CO2
usage.
• EOR fields are generally governed under a
petroleum act. Transition to CCS issues will
include, but are not limited to …
– Long term liability.
– Different rules / regulations for well
abandonment and reclamation.
– Stewardship fund.
– Pore ownership issues.
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13. GLOBAL CCS INSTITUTE
TRANSITION TO CCS
Why Transition?
– Why not blow the field down and sell the CO2
to the field down the road at a discount.
Until there is a value for stored CO2, this is always
a possibility.
Ultimately, there is no issue as long as the CO2
can be tracked and accounted for.
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14. GLOBAL CCS INSTITUTE
TRANSITION TO CCS
• When will EOR finish?
– Many CO2 EOR floods have been running for
30 to 40 years. They will finish when it is no
longer economic to produce oil.
– In the later years, they will not import and
used additional CO2, rather they will recycle
the produced CO2.
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15. GLOBAL CCS INSTITUTE
TRANSITION TO CCS
Can CO2 injection (CCS) continue after EOR?
• Probably only in for limited volumes for some
fields.
– The field may be pressurized from the CO2
EOR activities.
– There are potential well issues.
– Monitoring may be an issue.
• Other fields may have none of these issues.
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16. GLOBAL CCS INSTITUTE
THE WELL ISSUE
1 mile
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17. GLOBAL CCS INSTITUTE
DURING 1950-1955, 1 WELLS DRILLED
TOTAL NUMBER OF WELLS IS 1
1 mile
Initial Exploration Period

18. GLOBAL CCS INSTITUTE
DURING 1955-1964, 511 WELLS DRILLED,
TOTAL NUMBER OF WELLS IS 512
1 mile
Primary Production Period

19. GLOBAL CCS INSTITUTE
DURING 1964-1985, 141 WELLS DRILLED
TOTAL NUMBER OF WELLS IS 653
1 mile
Water Flooding Period

20. GLOBAL CCS INSTITUTE
DURING 1985-1991, 221 WELLS DRILLED
TOTAL NUMBER OF WELLS IS 874
1 mile
Water Flooding Period (Infill vertical Drilling)

21. GLOBAL CCS INSTITUTE
DURING1991-2000, 553 WELLS DRILLED
TOTAL NUMBER OF WELLS IS 1427
11mile
mile
Water Flooding Period (Drilling Horizontal Wells)

22. GLOBAL CCS INSTITUTE
DURING 2000-2011, 781 WELLS DRILLED
TOTAL NUMBER OF WELLS IS 2208
1 mile
CO2-EOR Operation Period

23. GLOBAL CCS INSTITUTE
THE KEY WELL ISSUES
• How to check, maintain and enforce well
integrity at a reasonable cost.
• Potential interference with neighboring
resources with different owners.
• How to ensure neighboring wells / fields within
the sphere of influence are maintained and
abandoned at the same technical level as in the
CO2 EOR field.
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24. GLOBAL CCS INSTITUTE
MONITORING ISSUES
Monitoring is necessary for CCS
• CO2 injected for EOR complicates monitoring
– what is old CO2 and what is new CO2
• The field has existing industrial and residual
chemical signatures. This would complicate
the monitoring signal / process.
• Baseline measurements are probably not
possible (too late).
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25. GLOBAL CCS INSTITUTE
CAN THESE ISSUES BE DEALT WITH?
YES! (1)
• Why store rather than re-use?
– A CO2 credit / tax will increase the incentive to
store CO2.
– Accounting regulations need to be established.
• When will CO2 EOR finish and CCS start?
– Not important as CO2 EOR currently stores CO2.
CCS can start as necessary.
• Are well integrity issues too onerous?
– No. Industry is dealing with them under current
regulations.
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26. GLOBAL CCS INSTITUTE
CAN THESE ISSUES BE DEALT WITH?
YES! (2)
• Can we monitor effectively without a baseline?
– More research into monitoring technologies and techniques may
have to be undertaken.
– Many “modern fields” are monitoring to maximize production.
• Is interference with neighboring resources (sphere of
influence issues) a deal breaker?
– No. Currently these issues are resolved through regulation.
– Specific regulations will have to be developed for CCS.
• Can CCS be implemented after CO2 EOR?
– This will be dependent on the specific field / reservoir properties.
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27. GLOBAL CCS INSTITUTE
DISCUSSION …
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28. GLOBAL CCS INSTITUTE
www.globalccsinstitute.com
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